In the 30-35 cc range are not that many choises.
The MVVS 35 is a excellent engine. Mine is turning 7800 with a MZ 20*10 on the pipe. In my case I could use the weight of the engine.
If you want to replace the OS, your weight penalty is to much in my opinion. A good alternative for the FX 1.60 is the 3W28.